Three blinking lights in nightsky of Bangor, Maine, helicopters searching the area.

I was in my room and heard what sounded like a helicopter hovering above. This was around 8:30 pm. At first, I just simply ignored the sound. But after five minutes, I decided to go outside. The sound was indeed that of a helicopter. However, as I looked up into the sky, I saw three lights blinking. The lights must have been about a few miles up in the sky, and equidistant apart (am not sure about the actual distance between each of the lights). Then, another helicopter arrived, circling the area above. As I am typing now, I can still hear the sound of at least one helicopter. They are definitely investigating the blinking lights, which I no longer see.